1. Related Application
The present application claims priority to Japanese Patent Application Number 2007-189048, filed Jul. 20, 2007, the entirety of which is hereby incorporated by reference.
2. Field of the Invention
The present invention relates to a method and a device for generating character data, a method and a control device for displaying character data, and a navigation apparatus. For example, the present invention preferably is applied to a navigation apparatus that is adapted to display a character string for a road name or the like by arranging multiple pieces of character data, each piece representing one character.
3. Description of the Related Art
A typical on-board navigation apparatus uses a dead reckoning sensor and a GPS (global positioning system) receiver to detect the current position of a vehicle, reads data of a map for the vicinity thereof, and displays the map on a screen. The navigation apparatus then displays a vehicle position mark indicating the vehicle position in a superimposed manner at a predetermined spot on the screen to allow at-a-glance recognition as to where the vehicle currently is traveling.
Road names are displayed in the vicinity of roads on a map on the display screen. Typically, a navigation apparatus that does not have a high-performance CPU (central processing unit) converts characters into bitmap (BMP) images character by character and stores the characters, in order to reduce the processing load for displaying the characters and to increase the display speed. The BMP data of characters that constitute a road name or the like are arranged sequentially to display one character string in a row on the map.
In general, navigation apparatuses used in the United States and Europe display road names along roads on a map. In many cases, roads are obliquely rendered, and thus, characters need to be rotated in order to cause character strings to be displayed along the oblique roads. FIG. 12 shows a state in which the BMP data of rotated characters are arranged in a row along an oblique road; As shown in FIG. 12, conventionally, when multiple characters are to be obliquely displayed in a row, the center point of the BMP data of each character is determined and the BMP data are arranged so that the center points lie on a straight line 500 that is parallel to the road.
For example, Japanese Unexamined Patent Application Publication No. 5-181412 discloses a technology in which the center point of a character string included in character data whose gradient angle is adjusted to substantially 0° is determined and the character string is displayed so that the center point matches a predetermined position on graphics data.
FIG. 13A shows an example of BMP data of a character at a regular position (where the rotation angle is 0°), and FIG. 13B shows an example of BMP data of a character obtained by rotating the regular-position character by a predetermined angle. As shown in FIG. 13A, for the regular-position character, BMP map data is created so that a center point 501 of the character matches the center point of the BMP data. However, as shown in FIG. 13B, when a rotated character is created through rotation of the regular-position character by a predetermined angle, a center point 502 of the rotated character and the center point of the BMP data may not match each other. Thus, when BMP data of multiple types of rotated characters are arranged so that the center points are aligned on one straight line, the bottom portions of the characters are not aligned with each other as shown in FIG. 14. Thus, there is a problem in that the characters look uneven from the viewpoint of bottom alignment.